Housing for an electromechanical component, particularly for a relay

ABSTRACT

The housing has a severable projection (3) at a housing wall in which projection a channel (33, 34) extends proceeding from the interior. The channel has at least two sections (33, 34) having different cross sections that become smaller from inside toward the outside in steps. As a result thereof, an aeration opening of differing sizes can be created for different applications of the component by parting the peg at different locations.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to a housing for an electromechanicalcomponent, particularly for a relay, comprising a housing wall tightlyterminating a gas-filled interior, whereby the housing wall forms aseverable projection toward the outside into which a channel extendsproceeding from the interior.

2. Description of the Related Art

In electromechanical components such as relays, there is often thedemand that they must be tight for soldering onto printed circuit boardsin order to avoid the penetration of liquid cleaning and solderingagents as well as of vapors. To this end, the housing is usually closedwith casting compound at the terminals side, as a result whereof thefeed throughs for the terminal pins and the gaps between the base andcap are closed. It has proven expedient, however, to provide such ahousing having plastic encapsulation with an aeration opening forfurther utilization after the soldering in order to prevent the creationof a contactdamaging microclimate in the interior of the housing. Thismicroclimate, for example, is influenced by inadequate heat eliminationwhen switching higher currents.

To this end, it is known from, for example, DE-U-80 17 121 to apply aprojection in the form of a hollow cone or cylinder to a housing cap ofa relay. This projection is cut off with a tool after the relay issoldered in, as a result whereof the channel extending from the interiorof the housing into the projection is opened up. The cross section ofthe aeration opening is prescribed by the channel cross section at thedefined parting location. When, thus, the relay should experiencediffering aeration for different applications and different switchingloads, this must be taken into consideration from the very outset bydifferent housing caps with correspondingly differently shapedprojections.

Given components such as relays having a large gas volume in thehousing, on the other hand, there is the problem that an over-pressurearises when sealing the housing with warm casting compound and whencuring this casting compound, this over-pressure leading either to poresat the seal locations or potentially causing a bulging of the housingcap. In order to avoid this effect, it is likewise already known toprovide an aeration hole in the housing for the main sealing process,this being subsequently closed by thermal deformation or by applying adrop of resin in case a complete termination of the housing is desirablefor soldering or for later employment as well. Such closable aerationholes that can also be accommodated in a peg were hitherto respectivelyprovided in a different form and independently of the afore-mentioned,hollow housing projections for subsequent aeration.

SUMMARY OF THE INVENTION

It is an object of the invention to create a housing for anelectromechanical component, particularly for a relay, whereby a housingprojection provided with an aeration channel can be employed in a singleembodiment thereof both for an aeration when sealing as well as for anaeration after the soldering, whereby the degree of aeration can also bedifferently selected corresponding to the application and to theswitching load.

In a housing of the species initially cited, this object is inventivelyachieved in that the channel in the projection has at least two sectionshaving different cross sections that become smaller in steps from insideto outside. The outside section of the channel comprising a smallercross section can thereby comprise an entirely or partially closedcross-wall in the form of, for instance, an injected skin. Thiscross-wall can be provided in a known way as terminating wall at the endof the projection; however, it can also be provided at approximatelymid-height of the outer channel section having a smaller cross section.This is especially advantageous when the cross-wall has a small aerationhole for the main sealing process of the housing, this to besubsequently closed. In this case, the cross-wall comprising theaeration hole together with that part of the appertaining channelsection open toward the outside forms a drip-on trough into which aresin drop can be introduced for subsequently sealing the aeration hole.Since this channel section in turn expands at the inside of thecross-wall, it forms a capillary block that prevents the resin drop fromflowing into the interior of the housing.

The projection of the housing also expediently has its outside contoursmatched to the graduated cross section of the inwardly disposed channel.Where the smaller channel cross section begins can thus also berecognized from the outside. One can thus easily see where theprojection is to be cut off in order to expose either a large or a smallaeration hole. The projection can thereby have the shape of a graduatedpeg that is provided in a housing part set back step-shaped, so that thepeg does not project beyond the general housing contour. The projection,however, can also be provided in the form of a rib fashioned graduated,for example as an improvement of the rib at a housing corner disclosedin DE-U-87 03 079.

The invention shall be set forth in greater detail below with referenceto an exemplary embodiment on the basis of the drawing. Shown are:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a cuboid relay housing having a projection in the form of a pegfashioned graduated;

FIG. 2 an enlarged cross section through the peg of FIG. 1;

FIG. 3 an enlarged plan view onto the peg of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The relay housing shown in FIG. I is essentially composed of a cap thatis put in place on a base member, for instance a pedestal, that cannotbe seen. For example, terminal pins can outwardly emerge in this basemember. The feed throughs of the terminal pins and the gaps between thecap and the base member are sealed in a known way, this not needing tobe shown and described in greater detail here.

At its upper corners, the cap 1 has a set-back step 2 on which aprojection in the form of a graduated peg 3 is arranged such that itdoes not project beyond the cuboid contour of the housing 1.

The specific fashioning of the peg 3 may be seen in the sectional viewof FIG. 2 and in the plan view of FIG. 3. In accord therewith, the peg 3is fashioned both inwardly as well as outwardly graduated, so that afirst section 31 having a larger cross section and a second section 32having a smaller cross section are formed, whereby the section 31 isseated immediately on the step 2 of the housing 1, whereas the section32 forms the free end of the peg 3. Of course, additional graduationscould also be provided as needed.

The peg 3 is hollow and thus forms an aeration channel that is incommunication with the interior 11 of the housing. A channel section 33having a large cross section lies in the region of the section 31,whereas a channel section 34 that likewise has a diminished crosssection lies in the region of the peg section 32. The channel section 34is also subdivided into two sub-sections 34a and 34b by a cross-wall 34that can be fashioned as an injected skin, whereby the cross-wall 35 inthe present example again has a central aeration hole 36. Dependent onthe application, this aeration hole 36 can be provided in the cross-wall34 from the very start or can be punched through later. It usuallyserves the purpose of enabling a pressure compensation while the housing1 is being sealed with casting compound. When this aeration hole 36 isto be closed later, then, for example, a resin drop can be introducedfrom above into the sub-section 34b that thus serves as a drip-ontrough. The widening of the channel cross section below the cross-wall35 acts as a capillary block, so that the resin drop does not penetrateinto the sub-section 34a or farther into the housing.

When the housing is to be aerated after, for instance, the component issoldered onto a printed circuit board, then either the section 32 or theentire peg having the sections 31 and 32 can be removed as needed. Thiscan occur, for example, in that the appertaining peg section is turnedwith a tool and then breaks off at the break surface 37 or at the breaksurface 38. An aeration opening having the cross section of the channelsection 34 or having the cross section of the channel section 32 iscorrespondingly opened.

The contours of the peg 3 seen from above are shown in FIG. 3. In thepresent example, the cylindrical cross sections at the opposite sides31a and 31b or, respectively, 32a and 32b are flattened. The peg canthus be more easily grasped with a pliers or with a socket wrench andcan be more easily sheared off by turning.

The channel sections in the peg 3 can be executed round, oblong-like orangularly. The illustrated fashioning in the upper part enables, first,a support of the male mold in the injection molding form and, thus,enables a longer useful life and greater stability of this form; on theother hand, the centrally disposed cross-wall 35 yields a reinforcementthat facilitates the described shearing of the peg.

The step-shaped projection, of course, can also comprise any other shapeand can be attached at other locations of the housing. For example, itwould be conceivable to provide a beveling corresponding to DE-U-87 03079 instead of the step 2 in the housing and to fashion the projectionas a peg or as a graduated rib on this beveling.

Although other modifications and changes may be suggested by thoseskilled in the art, it is the intention of the inventors to embodywithin the patent warranted hereon all changes and modifications asreasonably and properly come within the scope of their contribution tothe art.

I claim:
 1. A housing for an electromechanical component, comprising:ahousing wall that tightly terminates a gas-filled interior, said housingwall including a severable projection extending outwardly of saidhousing wall into which a channel extends proceeding from the interiorof said housing wall, said channel in the projection has at least twosections having different cross sections that become smaller from insidetoward outside of said housing wall in steps; and a cross-wall in anouter section of said two sections of the channel, said outer sectionbeing of a smaller cross section than an inner section of said twosections.
 2. A housing according to claim 1, wherein said cross-wall isat approximately mid-height of the outer section of said channel.
 3. Ahousing according to claim 2, wherein the cross-wall defines an aerationhole.
 4. A housing for an electromechanical component, comprising:ahousing wall that tightly terminates a gas-filled interior, said housingwall including a severable projection extending outwardly of aid housingwall into which a channel extends proceeding from the interior of saidhousing wall, said channel in the projection has at least two sectionshaving different cross sections that become smaller from inside towardoutside of said housing wall in steps; and an outside contour of saidseverable projection being shaped to indicate changes in the crosssection of the channel.
 5. A housing for an electromechanical component,comprising:a housing wall that tightly terminates a gas-filled interior,said housing wall including a severable projection extending outwardlyof said housing wall into which a channel extends proceeding rom theinterior of said housing wall, said channel in the projection has atleast two sections having different cross sections that become smallerfrom inside toward outside of said housing wall in steps, and saidhousing wall having a housing part that includes a sep-like set back andsaid projection being a peg on said housing part.
 6. A housing accordingto claim 5, wherein an outside contour of every section of said peg isin the form of a cylinder flattened at two opposite sides.
 7. A housingfor an electromechanical component, comprising:a housing wall thattightly terminates a gas-filled interior, said housing wall including aseverable projection extending outwardly of said housing wall into whicha channel extends proceeding from the interior of said housing wall,said channel in the projection has at least two sections havingdifferent cross sections that become smaller from inside toward outsideof said housing wall in steps, said projection being a graduated rib ata housing corner of said housing wall.
 8. A housing according to claim1, wherein said cross-wall is partially closed.
 9. A housing accordingto claim 1, wherein said cross-wall is entirely closed.
 10. A housingfor an electrical component having electrical contacts mountable withinthe housing, comprising:a housing wall defining an interior space forreceiving the electrical component; a projection extending from saidhousing wall, said projection including a passageway extending at leastpartially through said projection from the interior space defined bysaid housing wall, said passageway having a first portion of a lessercross section and a second portion of a greater cross section, saidsecond portion of said passageway being closer to said interior spacethan said first portion, said projection having an shaped externalsurface indicative of where said first portion of said passageway meetssaid second portion of said passageway so that said projection mayselectively be cut at said first portion or at said second portion. 11.A housing as claimed in claim 10, further comprising:a cross-wall insaid first portion of said passageway reducing the cross section of saidfirst portion at said cross-wall.
 12. A housing as claimed in claim 15,wherein said housing wall includes a step-shaped set back at one cornerof said housing wall, andwherein said projection is in said step-shapedset back so as not to project beyond a general housing contour of saidhousing wall.